Editor’s note: These abstracts have been edited for space and clarity. This program is current as of 15 January 2014. Additions, withdrawals and other changes to the conference program after this date may not be reflected. Click here for the most updated program.

A study on the application of ilmenite and hematite as weight materials for both water- and oil-based drilling fluids is presented in this paper. The study includes the effects of different size grades of the materials on rheology and fluid loss, as well as dynamic and static sag.

The paper will present relative abrasiveness of the materials compared to barite and recommend size grades that can minimize the abrasion effects. The paper will also report the results of magnetic property measurements, which impact operations of several downhole tools, and compares these with that of barite and several other minerals.

An innovative sand control technology is being developed that has the capability to totally conform to the wellbore and apply a positive stress on the formation face. It is a shape memory polymer with the capability to change geometric shapes.

The paper will present the results of additives added to completion fluids, giving the final fluid composition the ability to activate the polymer to its original shape and simultaneously clean up the filter cake left by the drilling fluid before the polymer reaches the wellbore.

An experimental study followed by comprehensive flow modeling is presented. The experiments were conducted on a horizontal well setup with drillstring under compression, considering the influence of rotation on frictional pressure losses of yield power law (YPL) fluids. Flow through various buckling configurations with and without drillstring rotation was investigated. A new correlation is presented for the transition from laminar to turbulent regions in concentric and eccentric annuli. A broad model of flow of YPL fluids is proposed for concentric, eccentric and buckled configurations.

Drill cuttings sub-surface injection, or cuttings re-injection, technology is one of the major widely used drilling waste management techniques and represents a process of drilling waste sub-surface injection via high pressure pumping above the injection formation’s fracture gradient. As any sub-surface operation, the cuttings re-injection has its own inherited risks and complexities, which must be addressed via front-end design. This is predominantly applicable to injection well, a core asset in the injection system and key to the success of entire drilling campaign.

The lessons learned and best practices discussed in the paper are believed to be of value for operators planning drill cuttings injection wells in their fields.

The paper discusses findings from experimental and analytical studies regarding HFTO the BHAs. With a two-pronged approach, potential sources of instability in drilling systems are critically examined. The interaction of the bit and the drilling system, which can generate self-excited vibrations, is investigated using analytical methods. Cutter-rock interaction as a possible excitation source is studied using laboratory experiments to elucidate the nature of dynamic cutting forces and their interaction with system effects.

The study identifies conditions in which the bit-rock interaction excites high-frequency torsional oscillations of the drilling system. The understanding gained can be used to mitigate torsional resonance and enhance drilling performance.

An extensive research study, including lab and field-testing, found that a low-frequency, benign axial vibration can increase the ROP significantly in all well types. Initial laboratory experiments were performed by inducing axial vibrations into the drilling process on a small-scale drill bit in hard rock. Dramatic improvements in ROP and drilling efficiency were observed, with the added benefits of improved bit life and an unexpected reduction in stick-slip.

A high-frequency, in-bit sensing device (1400-Hz sampling frequency) was installed into the bit shank in conjunction with a well-established MWD tool in the BHA. The intent was to capture the dynamics behavior of the BHA and the dynamics directly at the bit. The extended frequency range of the measurement module enabled the capture of new dynamics phenomena at much higher frequencies than are usually reported in the literature.

The insights gained in bit dynamics and cutter damage helped to improve bit design by building dynamically stable PDC bits with increased rates of penetration (ROP) and reduced NPT.

Phases I and II of the Macondo trial have concluded, and Phase III is expected to commence in early 2014. The paper will review pre-trial, trial and appellate court proceedings relating to the contractual indemnification, release and insurance provisions of the applicable drilling and cementing contracts that BP entered into with Transocean and Halliburton, respectively. The paper is intended to assist those involved in contracts and risk management in understanding the judicial proceedings and determining how they may impact oilfield contracts and insurance agreements.

IADC/SPE 167933

The Drilling Business Model: Driver or Inhibitor of Performance and Innovation, J.P. de Wardt, DE WARDT & COMPANY

The drilling business model has recently become the “elephant in the room” as drilling systems automation advances seek an integrator, and technology and performance enhancements seek rewards.

Discussing the current business models and opening the industry to development of more appropriate models has extremely high value and impact. It is a topic often raised and often left un-debated. If new business models are broadly adopted, it will change roles, performance, technology application and revenues throughout the supply chain. Awareness of these potential changes will be extremely important to managers and engineers in the drilling business.

NASA is currently pioneering work on using automated planning and scheduling to manage the work performed during extra-vehicular activities (EVAs) on the outside of the International Space Station (ISS). These EVAs are the most difficult activities performed by the astronauts on the ISS, and each one is planned to maximize efficiency and minimize risk.

This paper will describe the planning approach implemented for NASA, and will identify how that approach can be used to improve drilling
operations.

The experience gap is bridged by utilizing a decision support system that combines pattern recognition in time-series data with a machine-learning method called case-based reasoning. Real-time WITSML data is utilized to identify important elements of the down-hole situation, diagnose the current situation and predict possible outcomes.

This paper presents a case study from Kurdistan in which the technology was being deployed by OMV in an observation mode performing real-time analysis.

IADC/SPE 167994: Surface seismic while drilling (SSWD) allows for a relief well to hit the wellbore below the casing shoe, independent of casing or steel tubular in the well. SSWD is based on seismic sources and receivers on the seabed, and simulations have shown that it is possible to observe the well paths for the two wells.

Surface seismic while drilling (SSWD) could make it possible for a drilled relief well to hit the wellbore below the casing shoe. This method is not dependent on any casing or steel tubular present in the well to identify the relative wellbore positions. The SSWD is based on an array of seismic sources and receivers located on the seabed. Preliminary simulations indicate that it is possible to observe the well paths for the two wells. This method will allow online seismic monitoring of the well paths without interfering with the drilling operation.

The project discussed in this paper was conducted in deepwater offshore Indonesia and clearly showed some of the benefits of using MPD in deepwater drilling. The paper discusses both the planning and execution of two wells drilled by applying various forms of managed pressure drilling. The wells were drilled from a dynamically positioned (DP) drillship utilizing the world’s first known application of below tension ring rotating control device (RCD) as well as an annular preventer for riser gas handling below the slip joint.

Lessons learned associated with the installation of MPD equipment on a DP vessel and the procedures used to drill the deepwater carbonate formation are presented in the paper.

A challenging HPHT well was drilled with MPD. In the preparation phase, an advanced dynamic drilling simulator was used by the operator to test and verify operational procedures as well as the HPHT & MPD well control manual. This paper will briefly present the advanced drilling simulator, and focus on the testing and verification of procedures and well control manual. The modifications done will be presented and the operation itself will also be described, highlighting the benefits of utilizing the drilling simulator prior to operation.

TTD-1 has been identified as the deepest HPHT well ever drilled by PCSB in Malaysia. Managed pressure drilling (MPD) enabled the operator to drill and explore new sands and confirm new hydrocarbon reservoirs at 325°F with an undisturbed bottomhole pore pressure of over 14,000 psi. The MPD technique in conjunction with the best HPHT practices were able to overcome the most difficult planned and unplanned challenges while drilling this exploration well. The well was drilled to a depth of 15,847 ft (4,830 meters), and thus penetrated vast gas bearing reservoirs. This paper aims to share a case study of HPHT drilling practices combined with automated MPD that have been successfully adopted to explore new sands with minimal offset geological and petrophysics information.

The practice of drilling with MPD using statically underbalanced mud weight is gaining increasing acceptance in HPHT well construction. This paper describes the planning and execution of using mud cap fluid in the drilling of an ultra-narrow margin, 0.5 ppg window at the planning stage, HPHT well from a jackup.

IADC/SPE 167954

Improved Underbalanced Operations with Uncertainty Analysis, J. Udegbunam, University of Stavanger; H. Lohne, International Research Institute of Stavanger; K. Fjelde, University of Stavanger; O. Arild, E.P. Ford, International Research Institute of Stavanger

Uncertain parameters are treated as statistical distributions. These are propagated in the modeling process by means of Monte Carlo simulations. The predicted bottomhole pressure will no longer be a single value, but rather a statistical distribution. This may lead to a different result, compared to a modeling approach where uncertainty is not considered. By using a probabilistic approach, it is possible to quantify the chance of exceeding the operational limits of underbalanced operations, thus supporting operational decisions under uncertainty.

The aim of the paper is to further develop a model framework where uncertainties will be addressed. An example case for a vertical well, where different flow scenarios are considered, will be presented.

Continuous circulation provides an uninterrupted stream of data from sensors mounted downhole and on surface equipment even while making a connection thereby, never losing the site of downhole pressure.

Weatherford has developed a continuous flow system (CFS), including subs that are made up at the top of drill pipe stands and an automated control system for switching mud flow from top drive to side flow port and back. Significant features of the CFS are easy implementation on the rig, automatic switching of flow from standpipe to side entry port and back from a remote location, very high consideration to personnel safety, time saving for making connections and small footprint on the rig floor.

While the locations of critical-wear areas along the casing string have been predicted fairly accurately, quantifying the actual amount of wear itself has been a challenge. The existing casing wear models were developed only for static wear conditions where there is constant rotational contact between the tool joints and the inner wall of the casing. However, drilling activities and operating conditions have advanced rapidly, leading to several other downhole wear mechanisms contributing to casing wear. The paper presents field examples to predict and estimate casing wear using actual data. Estimation of casing wear using the new casing wear model was also performed using actual field drilling parameters, will be presented.

IADC/SPE 167932: The Drilling Complexity Index and the Planning Complexity Index are used to rate the complexity of well planning and operations during the project evaluation and planning phases to the execution phase.

By keeping the kicks small, they can be circulated out quickly without requiring conventional time consuming well control operations, which often lead to further hole problems. Coupled with dynamic pore pressure and dynamic formation integrity tests, real-time optimization of casing points can be achieved safely with reduced risk of costly well control incidents.

The method presented here, applicable to any deepwater well, uses low, expected and high pore pressure and fracture gradient estimates to develop an adaptive casing design for the well. In this paper, kick tolerance calculations for selecting casing points using MPD are defined. The method results in decision criteria that identify key depths where casing strings can be eliminated without compromising reaching the objective TD, following current design standards.

Casing and tubing are being increasingly used in drilling environments as an alternative to conventional drill pipes. Furthermore, OCTG tubular products are commonly rotated into place in horizontal and ERD wells. This paper describes the additional design considerations for casing or tubing strings when subjected to cyclic loads and also, whether to select a suitable connection for a given application, to set a limit on operative parameters for a given application and connection, or to assess the fatigue damage suffered by a given connection undergoing a certain application.

While milling conventional hanger systems have been performed before, there has been little experience with milling an expandable liner hanger. This paper summarizes the case history of the events leading to the collapse of a 9 7/8-in. liner over a 7 5/8-in. casing and drillstring, while drilling a depleted fractured reservoir (HPHT high inclination well) using the concentric tubular technique and MPD in the Cardenas field, south of Mexico. A new casing-design approach for wells under these challenging conditions has been developed and implemented as a result.

The Well Complexity Index (WCI) is composed of the Drilling Complexity Index (DCI) and the Planning Complexity Index (PCI). Wintershall has developed a Drilling Complexity Index and a Planning Complexity Index, which are simple systems used to rate the complexity of well planning and operations during the project evaluation and gated planning phases, from the conceptual or pre-screening phase through the detailed design phase to the execution phase.

The main objective of this research was to investigate the potential impact of the expandable casing technology on remediation of sustained casing pressure (SCP) due to gas migration. Varying magnitudes of SCP exist in the Gulf of Mexico, where in 2004, approximately 45% of 14,927 operational wells demonstrated gas leakage out of which cementing process was linked with 33% of those problems. Over 80% of casing strings exhibiting SCP are production and surface casings, which represents great technical, economic and environmental risk. These situations in which SCP is observed usually result in costly and unsuccessful remediation efforts.

IADC/SPE 168004: A scanning electron microscope was equipped with a hot-stage furnace accessory to allow for real-time observations of fracturing behavior of PDC cutters in simulated drilling conditions.

This paper presents a new mathematical model to determine the load on a constrained casing system in a deviated or vertical well, using the transfer matrix method (TMM). The distribution of forces along a tapered casing string in a deviated well are accurately calculated and the results will be presented.

Utilization of a drilling with liner system enabled a Russian operator to improve drilling efficiency, increase the ROP and drill deeper than expectations, resulting in higher production rates and a savings of 200 to 300 hrs of rig time compared to previous jobs. A premium hydraulic-set rotating liner hanger system and liner top packer allowed rotating the liner in hole with high torque.

TECHNICAL SESSION 6: INNOVATIVE BIT TECHNOLOGY

IADC/SPE 168000: The challenge of managing interbedded formations with competent stringers can be addressed by modifying the PDC cutter face geometry with shallow, recessed features.

Efficiently drilling the lateral hole section through the abrasive Colony Wash Reservoir sand in western Oklahoma creates a unique challenge. The highly heterogeneous formation was causing inconsistent PDC bit performance while constructing the 6 1/8-in. horizontal and thus damaging project economics. A study determined that improved ROI could be achieved by extending bit life in areas where poor drilling performance is expected.

To gain a more in-depth understanding of thermal fracturing behavior and its causes, a specialized environment was prepared that allowed in-situ observations of fracturing behavior in simulated drilling conditions. This included equipping a scanning electron microscope (SEM) with a hot-stage furnace accessory to allow for real-time observations and filling the chamber with a simulated atmosphere consistent with downhole conditions. Cutter cross-sections were selected and polished using new methods to ensure maximum clarity and then heated to fracturing temperatures, with the SEM recording all changes as they occurred.

Traditional PDC technology has made tremendous gains over the past decade with corresponding footage and rate of penetration (ROP) improvement in drilling performance. The remaining challenge is managing interbedded formations with competent stringers while maintaining drilling efficiency and the highest ROP potential. By modifying the standard planar PDC cutter face geometry with novel shallow recessed features, a demonstrated improvement in drilling efficiency along with an increase in attained footage was observed.

Traditionally, PDC drill bit selection is based on a perceived assessment of bit features that are fit for an application such as cutter size, blade count and gauge length. The resulting selections often neglect complex bit design trade-offs. This narrow focus creates unproductive design changes that are not rooted in drilling application requirements or performance issues. The approach described in this paper is an analytic process, relating applications and bit designs to a comprehensive set of common responses that are quantifiable, measurable and relatable to an audience with a wide range of technical expertise.

Stick/slip vibrations are known to cause damage to drill bits and other drilling system components. Recent investigations determined that the design of PDC bits has a significant influence on stick/slip behavior of the drilling systems. Among various bit design methodologies, a depth-of-cut (DOC) control technique has emerged as an effective way of mitigating bit-induced stick/slip.

A comprehensive testing program on a full-scale research rig was undertaken to characterize the optimal type, positioning and extent of DOC control required for mitigating stick/slip.

Test wells in the São Francisco basin have identified a vast opportunity for onshore natural gas production from unconventional tight sandstone and carbonate formations. The prospect is attractive because of its relatively shallow depth that varies from 2,000 to 4,000 meters, but constructing the 12 ¼-in. and 8 ½-in. vertical hole sections through the highly dipping formations and complex fracture zones has presented a number of distinct challenges when drilling with a conventional motor/PDC bit.

Vertical wells are drilled in the Colombian foothills with various types of drill bits, including PDC bits, tungsten carbide insert (TCI) bits, and impregnated (impreg) drill bits. A new 14 3/4-in. impreg bit was designed using an innovative new cutting structure to complete a challenging interval. This bit was paired with a low-speed power section & a high-speed power section in the BHA for two runs in the same well. Both runs did well, but the operator found the low-speed BHA to be a better match for the automated drilling system tool that was also in the BHA.

A study concluded the deepwater region of the Burgos Basin, east of the Mexican state, Tamaulipas, has high potential for hydrocarbon accumulations in a variety of trap styles. To test the hypothesis, the Caxa-1 exploratory well 150 km offshore would kickoff from 3.67° and build to 6° inclination, then drill tangent for 400 meters. The wellbore would penetrate shale overburden to evaluate Miocene sands at 3,400 to 4,000 meters before reaching TD (4,474 meters).

The challenge was to build an industry-first tandem reamer directional BHA. The objective would be to complete the section in one run and deliver all directional requirements at fast ROP with minimal vibrations to allow the use of advanced MLWD.

In a few years, there will be a need for performing a considerable number of subsea plug and abandonment (P&A) on the Norwegian Continental Shelf (NCS). There is a large focus on looking for rigless technologies to decrease P&A cost and use of rig time.

In this paper, a rigless technology for cutting and retrieval of wellheads is described. For the first time, a risk-based probabilistic approach including learning curves, correlations and possible risk events used to evaluate subsea batch P&A.

The increasing complexity of deepwater BHAs requires a complete systematic approach to each phase of the drilling process; pre-job planning, execution and evaluation. This approach was successfully applied to a recent multi well project in the Gulf of Mexico, whose vertical 12 ¼-in. by 13 ½-in. sections were historically plagued by shocks and vibrations while drilling. The root cause of inefficient drilling performance could not be accurately determined based on drilling data, but severe vibrations resulted in multiple downhole tool and BHA component failures.

With the implementation of a complete, holistic approach to the drilling system, the resultant effects culminated with no downhole tool failures and a significant reduction in drilling time and costs. The key was the multistage preparation process that was utilized.

Meticulous observation and analysis of 10 rigs participating in the rig move study yielded noteworthy data. Because of thorough measuring techniques and precise metrics, we were able to quantify the best methods for moving a rig. Documentation of the entire rig move process included rig up and rig down sequences, handling systems utilized, transportation methods, as well as rig and pad site layouts and labor. Detailed time and motion studies provided data separated by piece of equipment and measured to the nearest minute.

Based on the learnings and experience, a new and enhanced version of the drillstring network has been developed. This second generation high-speed drillstring network includes improvements to the design of wired drillpipe, a new generation of distributed network electronics and a graphical surface network controller. These enhancements, and their utility with respect to improving drilling processes, will be discussed in detail.

Sour service drill pipe have long been used with tool joints and tubes meeting separate criteria for sour service as defined by several industry standards. However, the new challenges associated with the particularly sour fields require new highly engineered drill string solutions in order to increase the safety margin related to sulfide stress cracking (SSC) failure risks, especially in the welded zones.

A new drill pipe configuration has been developed including modified chemical composition and modified manufacturing process. These modifications allow for the improvement of mechanical properties performance and SSC resistance in the welded zone.

IADC/SPE 167986: Time and motion studies, in addition to documentation of rig-up and rig-down sequences, handling systems, modes of transportation and site layouts, were considered to quantify the best methods for rig moving.

Seven of the world’s 10 longest wells by reach and measured depth have been drilled by ExxonMobil as operator of the Sakhalin-1 project in Russia. This paper will provide an overview of how drill string torque capacity became a limiter to increasing penetration rate and kept the operator from extending their total measured depth capability. This limiter necessitated that the operator seek an alternate drill pipe connection with higher torque capacity. The design of the new drill pipe connection and results to date from field implementation will be presented.

Drilling of extended reach wells (ERW) and ultra-deep HPHT wells is the most compelling reason for drilling companies to look for alternative drill pipes that meet their requirements. In this study, the main focus is on the comparison of fatigue performance of steel drillpipe (SDP), aluminum drillpipe (ADP), and titanium drillpipe (TDP) in mild and severe doglegs. Fatigue performances of different drillpipes are compared, and it is shown that, depending on the drillpipe specification, applied torque, axial load and dogleg severity (DLS) of the wellbore, one type can function better than others and a one-size-fits-all is not an appropriate approach on the selection of drillpipe material.

Numerous cases of drill pipe overload failures have occurred while rotating and reciprocating the drill string under packed off conditions where circulation is either low or lost completely. This paper provides multiple case studies where packed hole conditions with lost circulation were present and drill pipe tubes failed from overload deep in the well with low tensile loads relative to the rated tensile capacity which is consistent with down-hole heating overload. The paper presents experimental data that demonstrates the effect of elevated temperature on material strength for S-135 drill pipe tube materials at temperatures ranging from room temperature to austenitic transformation temperatures.

IADC/SPE 167965: The second-generation high-speed drillstring network improves the wired drill pipe design and features a new generation of distributed network electronics and a graphical surface network controller. The controller expands network diagnostic capabilities and reduces the learning curve for network users.

API rotary-shouldered drill stem connections have a seal surface that is required to carry internal pressure. We assume that this seal will hold the pressure from routine drilling operations, but drill stem tests, stuck pipe or other special situations can apply much higher differential pressures to the drill string. Currently, there is no analytical solution for predicting the pressure that can be safely contained by one of these industry-standard connections.

This paper addresses that problem by developing a predictive pressure-capacity equation for rotary-shouldered connections.

Sour service drill pipes have long been used with tool joints and tubes meeting separate criteria for sour service as defined by several industry standards. However, the new challenges associated with the particularly sour fields require new highly engineered drill string solutions in order to increase the safety margin related to sulfide stress cracking (SSC) failure risks, especially in the welded zones.

A drill pipe configuration has been developed including modified chemical composition and modified manufacturing process. These modifications allow for the improvement of mechanical properties performance and SSC resistance in the welded zone.

Recent regulatory requirements in the oil industry have spurred a demand for extensive relief well planning for shelf and deepwater wells around the world. This paper discusses well planning, trajectory design and drilling as it applies specifically to relief wells. The goal of the relief well is to divert the pressurized hydrocarbons up a new wellbore in a controlled manner or to kill/cap the downhole blowout with heavy mud/cement.

IADC/SPE 167920: Bottomhole patterns (BHP) of a baseline bit (left) and a newly designed bit (right) on a high build-rate RSS show a smooth concentric BHP with the new design. An inclination hold and azimuth software system was used to enable the RSS tool to build an aggressive curve angle to drill in the lateral and eliminate an additional trip.

Apache Corp recently commenced horizontal drilling activity to develop shale gas reserves in Neuquen basin, Argentina. On one well, the curve was drilled with a 12 ¼-in. PDC bit on PDM. The challenge was to drill the curve/lateral with a high build-rate RSS and a single 8 ½-in. PDC in one run to eliminate a trip to change the drive system. The introduction of an inclination hold and azimuth software system would enable the RSS tool, created to build the aggressive curve angle, to continue efficiently drilling in the lateral, saving an additional trip.

A new gyro survey tool capable of operating at any attitude during the drilling process has been developed – an all attitude gyro while drilling tool. This paper describes a number of innovative technological advances that have allowed all attitude gyro while drilling (GWD) to become a reality. The new high angle GWD system is well suited to handle any wellbore placement needs. These include high inclination kick-offs, in-fill drilling, relief wells and the provision of improved accuracy in east-west wells.

The paper describes an analysis of the spiraling observed in four wells. The analysis relies on a novel borehole propagation model that results from considerations involving a bit/rock interaction law linking the forces acting on the bit to its penetrations, kinematics relationships relating the bit motion to the local borehole geometry and a beam model to determine the lateral force and moment at the bit resulting from the deflection of the BHA imposed by the stabilizers. The model leads to the formulation of a set of delay differential equations to evolve the borehole inclination and azimuth, with the configuration of the BHA embodied in the coefficients of the equations.

This paper discusses the results of a study on the benefits of automation, in general, and improved instrumentation and control capabilities, in particular, to the drilling efficiency in the presalt.

The objective of this study was to see how an improved or automatic control of the surface operating parameters can result in better, more accurate control of all the variables that affect the drilling process and efficiency. The parameters studied were the hole cleaning, the ECD, pressure transients (surge/swab), stick & slip, amongst others.

The paper will describe how the real-time systems were implemented for a number of global drilling operations without installing a real-time operation center. This approach enabled the decision makers in the field to access the experience of and support from the rest of the organization. By not installing a real-time operations center, the organization saved resources and encouraged the local teams to use the analysis tools themselves to manage their operational performance.

IADC/SPE 168017

Automated MPD and an Engineered Solution: A Case History in Western Canada, J. Baker, Schlumberger

In this paper, the authors will demonstrate how successful upfront engineering and automated MPD technology, along with capturing and executing critical lessons learned during operations, contributed to a successful 1500-meter lateral section in the Fahler F formation. During the drilling process, many of the operational limits set during the initial planning and engineering had to be re-evaluated. As the operational window began to shrink due to fracture-induced ballooning, it became critical to walk the pore pressure line and manage bottom hole pressure (BHP) accordingly.

This follow-up paper will serve to investigate the experience of a rig using such a system over the course of the last three years with the combination of established KPI’s, analysis of logged data and field performance data.

Drilling automation is a critical fixture of the modern drilling rig, and continuous reviews of automated rig floor processes are necessary to continually optimize the automation concept. Recommendations will be made for improved operational performance on future rig floor layouts.

A new system, utilizing a programmable logic controller (PLC) and position sensors, has been devised to reduce the chance for injury and enhance safety for power tong operators. The application of a logic controller on conventional casing running equipment is a significant step in reducing operator and equipment error and increasing the casing crew’s safety threshold. This paper will discuss the evolution of this system from conception to application.

This paper will show how flow rates and tripping speeds can be controlled or governed by a drilling automation system to avoid fracturing the formation or swabbing in fluids during tripping. The system works in a way that is similar to an ABS system on a car. Advanced calculations compute downhole pressures for different tripping speeds and flow rates. The foundation of this drilling automation system is an advanced transient model that takes into account hydraulic, torque and drag, and thermodynamic effects.

Current surfactants and solvents on the market have limited application in terms of temperature and type of drilling fluids. Using improved experimental methods, more than 3,000 different tests on more than 200 tensioactive blends were performed. Statistical analysis helped selecting the optimum chemistry as a function of the conditions (type of base oil, salinity, temperature). This paper describes their ease of implementation at field level (few chemicals in inventory to cover all situations and limited local laboratory testing) as well their successful application in several wells (case histories), where different types of non-aqueous fluids were used at various temperatures.

A computational fluid dynamics model has been developed to better understand the transport phenomena of intermixing multiple fluids. The fluid decay for the mud, spacer and cement systems is quantified in-depth for given downhole conditions of wellbore geometry, fluid properties, pump rates and casing centralization. The method allows the analysis of potential hydrocarbon production zonal isolation success and optimization of cement placement. A 3D visualization module has been developed as an aid to understanding the complex phenomena.

It is desirable that plugging materials self-degrade to leave undamaged formation for hydrocarbon production while maintaining sufficient stability to allow well completion. The main challenge is designing the lost circulation material to provide plug stability and cleanup within a desired time frame over a broad bottomhole temperature range.

Fiber-laden fluids have shown good fracture plugging behavior, depending on fluid velocity and flow rate. To apply this concept to lost circulation applications, we designed a novel, fiber-laden fluid that can easily be prepared on surface, allowing compatibility with bottomhole assemblies at high flow rate.

Nanomaterials, especially nano C-S-H and nanosilica, have been shown to be capable of accelerating cement hydration. These nanomaterials also tend to have the additional benefit of reducing the permeability and increasing the mechanical strength of cement-based materials. This study investigates the feasibility of using nanosilicas as cement accelerators in low temperature conditions and their effect on the mechanical properties of oil well cement during early ages.

The paper reports experimental results on the importance of obtaining good casing centralization during primary cementing for prolonging the lifetime of a well. Safe temperature intervals within which a given well can be operated are provided, together with research-based information on when to choose a more flexible annular sealant than cement. The study presents, for the first time, a detailed 3D visualization and quantification of the size and geometry of leak paths, thereby enabling them to be more efficiently remediated in the future.

TECHNICAL SESSION 12: DEEPWATER DRILLING

IADC/SPE 167916: A new ream-on-demand system was deployed in a 12 ¼-in. section of a deepwater Gulf of Mexico well to eliminate multiple trips to change out bottomhole assemblies.

The nature of pore pressure profile on deepwater Gulf of Mexico wells dictates the need for hole enlargement while drilling (HEWD) on several intervals. On a recent deepwater Gulf of Mexico Lower Tertiary well, pore pressure anomalies, high mud weight and associated equivalent circulating density (ECD) required the operator to raise a formation integrity test (FIT) to the maximum limit while drilling the 14 ½-in. by 16 ½-in. section.

To solve application intricacies, the operator elected to use a new-type ream-on-demand (ROD) system in the 12 ¼-in. section and eliminated multiple trips to change out BHAs.

IADC/SPE 167934

Effective Hydraulic Modeling and Field Data for Deepwater Horizontal Well With Low Drilling Margins in Unconsolidated Formation, N.K. Collins, Schlumberger

Effective hydraulic modeling was highly critical for successful drilling a pilot Well B in a deepwater development in the Gulf of Mexico. The drilling target was to link three reservoirs divided by fairly thick shale at angle. This difficult drilling environment mandated intensive reservoir drill in fluid maintenance practices with specific focus on fluid rheology and density with bridging materials optimization and acid-insoluble solids monitoring. The well was drilled to TD in the target time with an average rate of penetration of 40 to 60 ft per hr.

The paper will present the hydraulic modeling along with field monitoring data and summarize the lessons learned on Well B compared with an offset.

Deepwater wells traditionally feature two or three riser-less sections that present a unique set of issues. In recent successes in the Gulf of Mexico, many complications often encountered during riser-less drilling were overcome by utilizing technologies that had been previously used in later sections of the wellbore.

This paper presents case histories from successful deployments of available technologies to meet the demands of riser-less drilling challenges. Technologies in focus are rotary steerable systems, gyroMWD, survey management and acoustic measurements in large hole sizes.

This paper describes field cases where such a system was used in deepwater wells offshore Brazil. The wireless telemetry system took less time to rig up than the wireline equipment and allowed the test sequence to be adjusted during the test. The data was available during flowing and shut-in conditions. The paper reviews the benefits and limitations of the current technology and makes recommendations on how to use the technology most effectively.

To be able to set and run larger and heavier casing strings with hook loads approaching or exceeding 2.5 million lbs, an innovative heavy duty landing system has been developed and put on the market. Such systems must be capable of landing heavy loads while ensuring slip crush resistance. It includes an extended slip with enhanced design coupled with a new greasing system, a 2.5 million-lb landing carrier and a pipe with a thick walled high strength material section, a lightweight tube and a rotary shouldered connection.

In a recent Gulf of Mexico well, a 16-in. liner primary cement job secured the bottom of the section but did not cover sufficient height of the salt section to provide adequate zonal isolation and created an APB issue. A planned second stage cementing operation was performed using a new cementing valve that was tested to the same gas-tight regime as the V0 specification employed in ISO14310.

The paper will discuss the operation in detail and explain how performing a second stage cementing job “top-down” through a cementing valve, as opposed to conventional cementing circulation, resulted in full zonal isolation throughout the entire section and eliminated many of the issues described before.

A fit-for-purpose mobile offshore drilling unit (MODU) was recently installed with a dual Active Heave Drilling Drawworks (AHD) system. This system is based on two AHD’s mounted on both the port and starboard side of the derrick, while working simultaneously as a complete 1,000 ton hoisting system. Reduced slip and cut costs, increased tripping time and overall redundancy for an ultra-deepwater system were the initial goals of the AHD system layout, and field performance data will be reviewed from operations in the North Sea and the West Coast of Africa, from water depths ranging between 370 to 3,000 meters.

The second drilling campaign at the Chayvo field, located offshore Sakhalin Island, targeted the development of a new reservoir zone using extended reach wells from onshore. Record length wells beyond the current ERD envelope were required. Key challenges included high torque and drag, wellbore positioning in a thin oil column, wellbore stability, long horizontal completions, and downhole tool telemetry. This paper describes the operator’s experience with drilling these challenging wells that resulted in several new ERD records.

Drive systems, specifically PDMs, turbines and, in most cases. rotary steerable (RSS) tools, continue to see extended mean times between failures (MTBFs). Consequently, technical success rates on directional drilling campaigns have also improved. However, the gains have not translated into meaningful and sustainable operational efficiencies needed to drive down drilling costs. This paper will identify and discuss the reasons why gaps still exist between technical and operational efficiencies. In addition, specific evaluation steps, and solutions developed to consistently improve operational efficiency and reduce drilling costs, will be presented with supporting case histories.

Conventional drilling through lower intermediate intervals in the southern portion of the Alpine field on Alaska’s North Slope (ANS) has posed severe challenges, resulting in poor well delivery and AFE overruns due to accumulated trouble times. While unstable shale sections can be drilled without significant issues, hole collapse has caused problems while tripping out of hole and running casings.

This paper provides insights into the new steerable drilling liner technology and the field trial program. We cover the lessons learned and further improvement opportunities applicable to future deployments in this area.

This paper looks at a case study where a passive MWD ranging method uses both the output of the magnetic sensors from the MWD and the directional information calculated from an all-inclination GWD. This allows the calculation of the spatial relationship (distance and direction), between the drilling well and the fish, at 90 degrees of inclination. As the drilling sidetrack and the fish are at 90 degrees inclination and the two wellbores are not parallel, a high inclination gyro must be used to calculate the azimuth required for passive ranging calculations.

A blowout in HPHT deep well posed a major challenge while designing the relief well, which was necessary to bring the well under control. For the relief well it was necessary to carry out a comprehensive well design and operational planning, identification and mobilization of necessary equipment in a short time. This paper will describe the preparations made for this type of relief well in the region. The main challenge was to choose a suitable location as close and as safely possible, in such a congested mature oil field, taking into consideration all the safety aspects such as wind direction, surrounded wells, flame and heat created from blowout well, etc.

This paper presents innovative drilling systems that can be deployed, azimuthally oriented, hydraulically set and configured to initiate drilling, all in the same trip downhole without the need for a cement plug. The system includes a directional BHA which may include a rotary steerable system, a positive displacement motor or a turbo-drill, a roller cone or a PDC or an impregnated drill bit selected for the formation with appropriate attachment mechanism, a built-in deflector ramp for attachment with the drill bit and for maximum support and guidance to the directional drilling BHA, and a formation specific, expandable and hydraulically set anchor below the built-in deflector for three point firm grip with the hole wall to counteract rotational tendencies.

The introduction in 2013 of the newest generation of steerable motors with further reduced short BTB distance design helped the operator to overcome these challenges. The new system significantly improved drilling performance with excellent directional control.

This paper will discuss the design, testing and results of horizontal type wells drilled using the latest generation of steerable motors in the Niobrara unconventional shale play.

Although many shale oil wells have been drilled recently in the Eagle Ford shale oil field, wellbore stability problems in the oil shale reservoirs have not been understood fully. In this study, we first determined the mineralogy of oil shale core samples from the Eagle Ford field. We also performed unconfined compressive strength (UCS) tests in order to investigate the effect of temperature on the compressive strength of core samples. Experiments have shown a distinct change in the mechanical properties of the rock. Theses effects will be discussed in details. The effect of these changes on the drilling and fracturing phases will be also discussed.

IADC/SPE 167945

The Use of Modeling to Enhance the Analysis of Formation Pressure Integrity Tests, M.W. Alberty, Hess Corporation; M.R. McLean, Consultant

The interpretation techniques of the result of formation pressure integrity tests (FPIT) most frequently focus upon the point at which a fracture first initiates, the point where unstable fracture growth begins, or the closure pressure of the fracture when pumping ceases. However, the early pressure build-up behavior is often overlooked and can provide much insight on the integrity of cement, the point of initiation of a fracture, the permeability of the formation being tested, the need for a cement remediation and the potential to increase fracture resistance using wellbore strengthening techniques.

This paper presents a model for predicting early pressure build-up behavior, discusses how the model can be used to significantly improve the interpretation of FPIT tests and provides examples of the application in select wells.

IADC/SPE 168041

Wellbore Strengthening and Casing Smear: The Common Underlying Mechanism, E. van Oort, O.S. Razavi, University of Texas at Austin

In the paper, we offer a re-examination of previously published data, such as open-hole leak-off tests, and theoretical results and present our own independent results and assessments to show that wellbore strengthening (WBS) and casing smear effect (CSE) have a common, unified origin. It will be shown that the only mechanism that explains all the data obtained to date is, in fact, the fracture propagation resistance (FPR) mechanism. Guidelines will be presented to exploit FPR optimally for the benefit of complex well construction, such as ultra-deepwater wells with tight drilling margins.

Several hundred tests have been performed to investigate the applicability, effectiveness and engineering of various strengthening wellbore techniques. The experimental techniques included simulated fractures by two plates or sandstone blocks with a borehole. In the block test, two independent stresses were applied to the block faces parallel to the wellbore, which simulated horizontal stress anisotropy under downhole conditions. Drilling fluid, with and without LCM, was pumped into the wellbore to simulate breakdown, mud loss and fracture sealing.

This paper discusses another approach for designing lost circulation materials (LCMs) to be able to withstand higher wellbore pressures within a fracture. A property of plug breaking pressure (PBP) was determined for different LCM combinations, using a permeability plugging apparatus (PPA) with tapered slots. This work confirms that all LCMs are not equal and that the LCM type plays a role in terms of both plugging and toughness that better withstands displacement pressures.

Plugging existing fractures or fractures induced during drilling with lost circulation materials (LCM) is often used to increase the drilling window. Various techniques have been used, but the several factors affecting these procedures, known as wellbore strengthening, are not thoroughly understood.

This paper discusses wellbore strengthening factors, with the goal of better understanding of the several interacting events local to the wellbore and near-wellbore regions and improving operational considerations related to lost circulation events.

The aim of the study is to provide a geomechanical tool to analyze stress evaluation around wellbore for strengthening applications. An integrated geomechanics workflow that incorporates poro-thermo-elastic algorithms is introduced. Wellbore strengthening scenarios are simulated through this workflow using analytical solutions and field data.

The paper will present a case study of the circumstances when a vertical well ended up at 16° before the deviation was detected and a correction could be made.

Human error has come under the spotlight, and human factors are being included into well control training programs. Limiting such training to well control suggests that these enhanced skills are only necessary during abnormal events. Yet, as this case study will show, developing these skills brings benefits in avoiding what might be regarded as normal NPT incidents.

This paper examines how the petroleum industry could utilize and benefit from the available human reliability analysis (HRA) methods by applying them to daily operations. This paper also introduces several available practices and ongoing efforts for human error data collection implemented in the nuclear industry, including human event repository analysis (HERA), the Halden international empirical study, scenario authoring-characterization and debriefing application (SACADA).

The paper will summarize the principles of high reliability organizations and their contribution to process safety in the context of drilling operations. It will then briefly review an operational control framework within which non-technical skills training can be designed. The advantage of this approach is that effective non-technical skills can be observed, coached and assessed on a routine basis in the workplace. Active use of these methods in every-day drilling operations promotes the essential characteristics of a high reliability organization by instilling the sense of chronic unease and concern for barrier integrity, thereby reducing the chance of minor anomalies cascading into major accidental events.

IADC/SPE 167970

An Engineering Look at the Cause of the 2010 Macondo Blowout, J.A. Turley, The Brier Patch, LLC

The author examines two failures that allowed the casing shoe to leak, float collar and internal and annular shoe-track cement. After successful high-pressure tests, crews executed a negative-pressure test (NPT-1), using drillpipe and seawater, to simulate pulling the BOPs and riser.

The paper defines the sequential engineering and operating steps that led to and caused the blowout. The work is vital to ongoing industry-wide efforts to develop and improve drilling-process-safety, real-time data, and safety and environmental management systems.

Maersk Oil adopted a risk based process safety (RBPS) approach, originally developed by the petrochemical industry, but now also a recognized approach in the oil industry, to ensure effective management of process safety. RBPS is based on four main pillars and 20 key elements.

This paper describes the development of a questionnaire, now available as a web-based self-assessment tool that evaluates and measures the maturity of process safety understanding, commitment and implementation across locations and even across disciplines. It also describes how the assessment is being used for continuous improvement and management review.

This paper focuses on the incorporation of the aspects of culture and human factors into the management of this interface; complimenting the rudiments of process safety and personal safety. Five key aspects are explored: mission, communication, accountability, capacity and learning. By overlaying these aspects into the joint ownership and management of this interface, the industry collectively can make a step change as to how such safety risks are mitigated.

IADC/SPE 168005

Don’t Get Stung Setting Balanced Cement Plugs: A Look at Current Industry Practices for Placing Cement Plugs in a Wellbore Using a Stinger or Tail-Pipe, J. Roye, Schlumberger; S. Pickett, Chesapeake Energy

A stinger with a smaller diameter than the drill pipe is commonly run on the bottom of the work string for setting a balanced plug. A mathematical analysis of what occurs once dynamic conditions begin by pulling out of hole (POOH) with a small diameter stinger shows that the initially balanced system quickly becomes unbalanced.

This analysis of placement technique can be valuable for any situation in which a balanced plug would normally be used for plug placement. By looking at the changing conditions while POOH with a stinger, it can be concluded that using the balanced plug method will result in the contamination and potential failure of the plug.

TECHNICAL SESSION 16: PERFORMANCE EXCELLENCE

IADC/SPE 167949

The Majnoon Field: A Case Study of Drilling Operations in a Remote Area of Iraq, J. Le Vesconte, Halliburton; R. Tinkhof, Shell; P. Hardman, The REACH Group

Iraq presents many challenges to international oil and gas producers. This paper will discuss one such operation, the giant Majnoon oilfield. The field was discovered in 1975. Following the drilling of 20 wells, operations were suspended due to the Iran-Iraq war. After the war production resumed, however drilling did not re-commence until 2011.

Leak-off tests (LOTs) are routinely performed by the drilling industry after drilling a few feet below a new casing shoe. The recorded leak off pressure (LOP) primarily establishes the upper mud weight (MW) limit for the next hole section. Field-wide LOP data usually shows some spread at a given depth. Lower bound trend of LOP data is used as the base case for fracture pressure prediction and planning of future wells.

This study highlights the caution needed in interpreting LOP values in inclined wells drilled in different azimuths. Depending on horizontal stresses anisotropy, LOP measured in inclined wells may need a careful scrutiny of the trajectory vis-à-vis stress direction before consideration in well design.

IADC/SPE 167931

Dynamic Modeling of Gas Distribution in the Wellbore During Kick Situations: The Solutions, C. Gruber, University of Leoben; H.F. Spoerker, OMV Exploration/Production; W. Brandstaetter, University of Leoben

For decades, well control models have been based on the assumption of a more or less single-phase gas bubble present in the annulus and slowly migrating upwards after shut-in. While this approach satisfies straightforward volumetric well control aspects, it ignores solution and chemical reaction-kinetic effects. Especially when investigating sour gas (i.e. hydrogen sulfide) influxes into high-pH drilling fluid systems, the prediction of actual downhole pH development during shut-in and well-killing operations is of prime interest when deciding on potential damage to high-strength drill string components (> 110 ksi tensile strength) due to sulfide stress cracking.

While data from the US Federal Bureau of Labor Statistics has shown the trend for injury accidents has been steadily declining, incidents of NPT have gone up significantly. A Middle East operator has been investigating various technologies to facilitate improvement and reduce NPT issues. The provider has applied a strategic combination of services and modeling systems to achieve the objective including a real-time artificial neural network (ANN) drilling parameter optimization system, which provides information to ensure maximum run length from all bits and downhole tools at the highest possible ROP.

The Bricol field is a naturally fractured reservoir, located in southern Mexico primarily producing from a deep objective in the Upper Jurassic Kimmeridgian formation. The geological complexity includes fracturing, salt bodies and HPHT, generating unexpected conditions that suddenly change bringing several problems associated to the drilling operation.

This paper will give a detailed description of the problems encountered and the unique solution that was developed to solve this problem on future wells, during the planning stage through sensitivity analysis to improve the trajectory.

TECHNICAL SESSION 17: CASE STUDIES

IADC/SPE 168040

Incorporating Completion and Drilling Techniques to Enhance and Maximize Production Over the Life of the Well, L.M. Smith, Alaskan Energy Resources; G. Scott, Western Energy Products and Services

This paper describes the use of a multi-faceted approach that begins with combining the requirements of drilling and production groups. Additionally, this strategy integrates specific objectives and technology for improving the success of landing the liner on depth and helping drill a cost effective, smooth gauge hole. The paper describes the specific design features to incorporate and discuss with regards to packer design, reamer, centralizers and T&D equipment.

The drilling of hard abrasive volcanic rock has presented significant technical challenges to bit manufacturers over the years. This paper will focus on the development of a unique concentric two-stage dual-diameter PDC bit that was coupled with a low speed high torque mud motor to provide an alternate technical solution to drilling a challenging section featuring a hard volcanic layer for a major international operator in a remote location west of Shetland.

The paper reviews the design concepts of the bit that allow an initial smaller pilot hole to be drilled that has the effect of stress relieving the surrounding rock.

To increase production in East Zeit field, the operator wanted to recover a slot occupied by a well with collapsed 30-in. conductor. A whipstock system was required that could anchor in the 30-in. casing, enabling a full-gauge 16-in. window to be milled for sidetracking. However, there are no whipstocks made with anchors large enough to set in 30-in. casing.

A unique solution was proposed: set two joints of 20-in. casing in-slips before running the whipstock; set a 16-in. cased-hole WS using an expandable anchor just below the rotary table inside the 20-in. casing; pull the entire assembly and hand-cut the window in the 20-in. casing; run in hole with the whipstock inside the 20-in. casing and cement in place; access and mill an exit through the 30-in. conductor through the 20-in. casing’s precut window.

A novel, real time drilling optimization system is shown to improve drilling performance by increasing the rate of penetration (ROP) while extending the length of the bit run. Additionally the optimization system reduces the wear and tear on the drill string realizing additional cost savings by avoiding equipment redress charges. The result is lower total cost to drill the well. To date, seven wells have been drilled utilizing the optimization system.

IADC/SPE 167915: The accuracy of pore pressure prediction methodology was analyzed to try to enhance pore pressure modeling techniques. This paper will compare a new seismic frequency method with seismic interval velocity and petrophysical methods.

Pore pressure prediction is a key aspect in well design, and it often proves to be one of the most difficult components to accurately access. With oil and gas plays moving to increasingly less conventional drilling environments, there is a great industry wide need to enhance our pore pressure modeling techniques. To address this issue, an analysis of pore pressure prediction methodology accuracy has been conducted. The relatively new seismic frequency based methodology for pore pressure prediction is presented and compared to other, more commonly applied seismic interval velocity and petrophysical methods.

A new cutting element has been developed that can mill up to double the previous number of composite plugs or frac seats, allowing most wells to be milled in a single trip. The previous record for the most plugs drilled out with a single mill was 40, and a mill dressed with these new elements removed 79 plugs in two different wells. It also holds the record for the most plugs removed from a single well after drilling out 52 in a single trip.

Near bit sensors are located only a few feet behind the bit compared to traditional MWD sensors, which are often more than 20 ft behind the bit, thus, allowing for the opportunity to exit thin bed formations before the formation change can be observed on the logs. These tools are also instrumental for choosing the formation tops as each new boundary is drilled. The Gamma-At-Bit-Inclination Sensor (GABITM) provides at-bit azimuthal gamma ray and inclination measurements for improved geosteering and optimum well placement. This paper presents two case studies where GABI was successfully used for optimal drilling and precise well placement.

This paper highlights the design, execution and evaluation of the first application of turbodrill and hybrid bit to drill cretaceous formations with up to 40% chert content in Mexico south region. The goal of the application of a new drilling system was to reduce the need to trip for TCI bits drilling hours limitations and optimize flat times; reduce rotary steerable system (RSS) failures; deliver a wellbore with minimal tortuosity, which enhances wellbore evaluation and liner running; eliminate the risk of fishing for lost cones.

This work aims to present the development and result of experiments performed at a large scale drilling fluid loop, aiming the evaluation of commercial and built in property sensors. The following properties were determined: rheological parameters, mud weight, water-oil content, emulsion electrical stability (for oil based muds), fluid conductivity (for water based muds) and particle size distribution.

This paper covers the experience of one service company in the field deployment of high-temperature drilling equipment that can be used in environments up to 350°F (175°C) and at pressures of 30,000 psi. The authors use detailed case histories to show how system consisting of high-temperature MWD system and high-temperature RSS provided a true step-change in drilling performance in this challenging environment.

This paper will describe experiences, challenges and approaches to solving the problems related to creating an advanced early kick detection system suitable for floating mobile offshore drilling units. Necessary components, operational considerations and design limitations will be discussed. Additionally, a discussion will be offered on the current state of regulatory requirements related to kick detection and considerations for future standards.

Foamed cement operations require not only a better understanding of foam quality during placement, but also good control of nitrogen injection. This will ensure well security during placement and provide well integrity after placement. Several case studies of foamed cement jobs performed in Gulf of Mexico are presented where the use of both real-time process control and dynamic placement simulations resulted in successful execution and proper cement placement.

The bedding planes, anisotropic elasticity, time-dependent mechanical behavior introduced by fluid-mechanical interaction and rheology of rock formations, strength hardening/softening, etc. have tremendous impacts on the mud weight selection for safe drilling through shale. This work shows that a numerical code, which can accommodate all these factors, is a suitable tool for calculating safe mud weight with the said complications considered.

IADC/SPE 168057

A Field-Based Method of Calibrating Inclinometers for Floating Drilling and Completion Operations with Applications of the Method to Reduce Differential Flex Joint Angles, D.E. Mouton, BP; D. Newberry, University of Houston

Inclinometers in deepwater drilling and completion operations provide essential information for decisions involving millions of dollars. This paper presents a field-based method of mathematically correcting inclinometer readings to obtain true readings for decision processing. A method to reduce the subsea differential flex joint angle between the BOP’s and the lower flex joint is detailed. By minimizing this angle, operational problems and/or potential damage to subsea pressure containment equipment can be reduced.

To help ensure proper performance of a cementing operation, various evaluation techniques and tools have been developed and used through the years, including some based on ultrasonic pulse-echo technology. The evaluation system developed in this study consists of a combination of various validation media with a wide range of acoustic impedances (1.5 to 8.5 MRayls) and a multi-casing fixture with casing wall thicknesses ranging from 0.4 to 1.4 in. This system was employed for evaluation of tool performance in the presence of various muds and across a range of temperature and pressure conditions.